CVE-2003-0718 in Windows
Summary
by MITRE
The WebDAV Message Handler for Internet Information Services (IIS) 5.0, 5.1, and 6.0 allows remote attackers to cause a denial of service (memory and CPU exhaustion, application crash) via a PROPFIND request with an XML message containing XML elements with a large number of attributes.
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Analysis
by VulDB Data Team • 08/11/2025
The vulnerability described in CVE-2003-0718 represents a critical denial of service flaw within Microsoft Internet Information Services versions 5.0, 5.1, and 6.0 that specifically targets the WebDAV Message Handler component. This vulnerability operates through a sophisticated exploitation vector that leverages the structured nature of WebDAV protocols and XML parsing mechanisms. The flaw manifests when the IIS server processes a PROPFIND request containing malformed XML data with an excessive number of attributes within XML elements, creating a condition that leads to resource exhaustion and system instability.
The technical implementation of this vulnerability stems from inadequate input validation and memory management within the XML parser component of IIS WebDAV handler. When processing a malicious PROPFIND request, the server's XML parser attempts to parse XML elements containing an unusually high number of attributes, causing exponential memory consumption and CPU processing overhead. This parsing operation becomes increasingly resource-intensive as the number of attributes grows, leading to memory allocation failures and eventual system crashes. The vulnerability operates at the application layer and can be classified under CWE-400 as "Uncontrolled Resource Consumption" with specific characteristics of CWE-129 as "Improper Validation of Array Index" and CWE-770 as "Allocation of Resources Without Limits or Throttling".
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the entire web server infrastructure. Attackers can trigger memory exhaustion that causes the IIS service to crash repeatedly, resulting in prolonged denial of service conditions that can last for extended periods. The CPU exhaustion aspect means that legitimate users may experience degraded performance or complete service unavailability as system resources become consumed by the malicious parsing operations. This vulnerability particularly affects organizations relying on WebDAV functionality for content management, document sharing, and collaborative environments where IIS serves as the primary web server platform. The attack can be executed remotely without authentication requirements, making it particularly dangerous as any network-accessible IIS server with WebDAV enabled becomes a potential target.
The attack pattern aligns with ATT&CK technique T1499.004 for "Endpoint Denial of Service" and demonstrates how XML external entity processing can be weaponized for resource exhaustion attacks. The vulnerability exists in the parsing logic where the XML processor does not implement proper safeguards against malformed input structures, allowing attackers to craft payloads that cause disproportionate resource consumption. Organizations should consider implementing network-level protections including firewall rules that restrict access to WebDAV endpoints and intrusion detection systems that can identify and block malformed XML requests. The most effective mitigation strategy involves applying Microsoft security patches that address the XML parsing vulnerabilities in IIS WebDAV handlers, combined with implementing input validation controls that limit the maximum number of attributes allowed in XML elements. Additionally, organizations should consider disabling WebDAV functionality when not required and implementing resource monitoring to detect unusual memory and CPU consumption patterns that may indicate exploitation attempts. This vulnerability serves as a classic example of how seemingly benign XML processing capabilities can be exploited to create significant operational impacts, highlighting the importance of proper input validation and resource management in web server implementations.